Isaiah Whitehead’s goal was to turn the program around, picking Seton Hall when nobody of his All-American stature would. He wanted to change everything in South Orange, to make the Pirates a winner, be remembered as the player who got Seton Hall back to where it was in its heyday of the 1990s.

It took him — and the rest of coach Kevin Willard’s blockbuster recruiting class — less than two years to do so.

The phenom from Lincoln High School and Coney Island already had third-seeded Seton Hall in the NCAA Tournament, guiding them to a surprising third-place conference finish, but the last three days he wrote his name into Pirate lore, leading the New Jersey school to its first Big East Tournament crown in 23 years.

“It’s like picture-perfect,” Whitehead said after his three-point play with 18.5 seconds left capped a memorable title game and thrilling 69-67 victory over top-seeded Villanova in front of a sellout crowd of 19,182 at the Garden. “Coach believed in me, my team believed in me. I’m at the top of the Big East, we’re at the top of the Big East. That’s where we wanted to be.”

Whitehead, the tournament’s Most Valuable Player, scored 26 points — his seventh straight game of at least 20 points — and his teammates locked down the explosive Wildcats, beating them for the first time in three tries, holding them to 10 points below their regular-season average and limiting them 42 percent shooting from the field.

“We just went out there and played our hearts out,” said sophomore forward Ismael Sanogo, Seton Hall’s defensive specialist who had eight points and nine rebounds. “It was just grit.”

Seton Hall (25-8) was the better team in the first half, shooting 56 percent from the field and leading by as many as 14. Villanova (29-5), the defending conference champions who still may get a No. 1 seed in the NCAA Tournament, played with an edge after the break, pulling even on Kris Jenkins’ 3-pointer with 9:15 to go.

Jenkins (23 points) gave Villanova its only lead of the second half with 52 seconds left, draining his fifth and final 3-pointer of the evening that looked like it may stand up after Whitehead made only one of two free throws on the ensuing possession. But Seton Hall forced a 5-second violation out of Josh Hart, Whitehead hit a right-handed runner off the glass and sank the accompanying free throw with 18.5 seconds left.

“I’m from Brooklyn,” Whitehead said. “I’m not going to back down.”

Sophomore Desi Rodriguez, Whitehead’s high school teammate, said: “I saw his toughness. I looked in his eyes, and I knew he was going to make a big play. That’s just him. He’s determined to win.”

Jenkins missed a 3-pointer on the other end, Hart was blocked on the follow, and when Ryan Arcidiacono’s desperation heave fell well short at the horn, Seton Hall stormed the court, its gleeful players from New York City and New Jersey deliriously dancing on the Garden floor.

“It’s awesome — it’s awesome for them, to have their family, their friends watch them do it,” Willard said.

It was hard to imagine such a celebration at this time last year, following nine losses in 10 games to close the year, ruining a once promising season. Whitehead drew criticism, despite missing five weeks with a stress fracture in his right foot, and Willard was on the hot seat, unsure if he would return.

In a postseason sit-down with athletic director Pat Lyons, he guaranteed they would win next year, Willard was so confident in his group of young players. Now he joins P.J. Carlesimo as the only coaches to lead Seton Hall to a Big East title.

The league’s coaches weren’t convinced in October, picking Seton Hall seventh. Just a few weeks ago, the Pirates were considered to be on the bubble. Now, after back-to-backs wins over fifth-ranked Xavier and No. 3 Villanova, they could land a No. 4 seed, potentially get to play the opening weekend in Brooklyn, Whitehead’s home borough.

“Whoever we play, better watch out,” Whitehead said. “We defend at a high level, and we’re up to the challenge.”